Example #1 write the chemical formula for Calcium Oxide
Step 1
-Find the Atomic symbol of the metal and non-metal on the periodic table
CaO
Step 2
Find the charges for Calcium and Oxygen
which are Ca 2+ and O 2-
Step 3
Balance out the charges
They are already balanced out
Here´s the chemical formula for Calcium Oxide
CaO
Example 2 write the chemical formula for Aluminum Oxide
Step 1
-Find the Atomic symbol of the metal and non-metal on the periodic table
A
l
O
Step 2
Find the charges for Aluminum and Oxygen
Which are Al 3+ and O 2-
Step 3
Balance out the charges
You need 2 Aluminum and 3 Oxygen to balance the charges
Al 3+ O 2-
Al 3+ O 2-
= 6 + O 2-
= 6-
Step 4
If you need more then one element to balance out the charges you identify that by using subscripts
Heres your chemical formula for Aluminum Oxide